The present study was designed to evaluate the effects of
synthetic ACTH (1-24, tetracosactid) and porcine CRH on the plasma levels of
cortisol and
PGF2alpha metabolite in cycling gilts (n = 3) and castrated boars (n = 3). The experiments were designed as crossover studies for each gender separately. Each animal received, during three consecutive days; 1)
ACTH (
Synacthen Depot) at a dose of 10 microg/kg
body weight in 5 ml physiological saline, 2) porcine CRH at a dose 0.6 microg/kg
body weight in 5 ml physiological saline or 3) physiological saline (5 ml). The test substances were administered via an indwelling jugular
cannula in randomized order according to a Latin square. The administration of
ACTH to cycling gilts resulted in concomitant elevations of
cortisol and
PGF2alpha metabolite with peak levels reached at 70.0 +/- 10.0 and 33.3 +/- 6.7 min, respectively. Similarly, the administration of
ACTH to castrated boars resulted in concomitant elevation of
cortisol and
PGF2alpha metabolite with peak levels reached at 60.0 +/- 0.0 and 20.0 +/- 0.0 min, respectively.
Cortisol peaked at 20 min after administration of CRH in both cycling gilts and castrated boars with maximum levels of 149.3 +/- 16.5 nmol/l and 138.3 +/- 10.1 nmol/l, respectively. It can be concluded that administration of
synthetic ACTH (tetracosactid) to pigs caused a concomitant elevation of
cortisol and
PGF2alpha metabolite levels in both cycling gilts as well as castrated boars. The administration of CRH to pigs resulted in an elevation of
cortisol levels in both cycling gilts and castrated boars. Conversely,
PGF2alpha metabolite levels were not influenced by the administration of CRH either in cycling gilts or in castrated boars.